Mr Marius Petersen (or Pedersen), was born 19 July 1887 1 at Tåglund, Nysted, Maribo County, Denmark to Karen Sophie (nee Petersen; she may have been born 10 February 1863 in Birket, Toreby, Maribo) Petersen, who was an unmarried mother.2 He was christened 19 February 1888 in the Church of Denmark tradition in Maribo. His godparents were farmer Rasmus Hansen and his wife, who lived at Tåglund.
His childhood seems to have been slightly troubled, with him living in different places in different families over the years. In 1890 he was a foster son in the family of Rasmus and Birthe Clausen who lived in Saksköbing, Musse, Maribo. In 1901 he lived in Vester Ulslev, Musse, Maribo, as a foster son in the family of Rasmus, a farmer b. 31 December 1846, and Karen (née Jörgensen; b. 16 July 1847) Nielsen.
By 1906 he was a milk driver living in Birket, Toreby, Maribo, Denmark, and in 1911 he was a dairy worker (mejerist) living in Femö, Fuglse, Maribo.
Petersen seems to have emigrated to England later in 1911 or possibly in early 1912. The White Star Line listed his address as 73, West End Road, Southall, Middlesex, and the passenger list stated he was a dairy worker from Denmark aged 24.
Petersen boarded the Titanic at Southampton as a third-class passenger, although some sources suggest he did not sail at all since he sought to have his ticket refunded or rescheduled.
Southall Man's Fortunate Decision
An extremely fortunate eleventh-hour decision prevented a Southall man from being involved in the terrible calamity that on Sunday night befell the "Titanic." Mr. Marius Petersen left his many friends in Southall with the intention of journeying to America on the ill-fated liner, on which be had already booked his passage. On learning the awful news of the disaster, and seeing Mr. Petersen's name included in the list of third-class passengers published on Wednesday, his Southall friends were quite prepared for the worst. They were overjoyed, however, when later on in the day they received a letter from him, dated from a port in Holland, in which he stated that he had altered his mind and was not going to America for a month or two, and that he intended to endeavour to get the White Star Company to vary the date of his ticket. - West Middlesex Gazette, 19 April 1912
As far as can be ascertained Petersen did travel and died in the sinking3, his body was never found.